In a conventional image encoding method based on the H.264/AVC standard, CABAC (Context-Adaptive Binary Arithmetic Coding) and CAVLC (Context-Adaptive Variable Length Coding) are defined as entropy coding. Between these, the CABAC is a binary arithmetic coding method for performing adaptive coding according to the surrounding conditions (context).
In the H.264/AVC standard, when parsing slice data, the CABAC initializes an encoding process engine, a decoding process engine, and the value of context in the head of the slice data (for example, refer to Non-Patent Document 1).
At present, to achieve higher encoding efficiency than that of H.264/AVC, an image encoding technique called HEVC (High Efficiency Video Coding) is being developed as a standard by JCTVC (Joint Collaboration Team—Video Coding), which is a joint standardization organization of ITU-T and ISO/IEC. Non-Patent Document 2 has been issued as a draft of HEVC.
At present, in the draft of the HEVC, an adaptive loop filter (for example, refer to Non-Patent Document 3) and an adaptive offset filter (for example, refer to Non-Patent Document 4) are adopted. In the HEVC, an adaptive offset filter is provided between a deblocking filter and an adaptive loop filter.